org.springframework.boot.actuate.metrics.export.MetricCopyExporter.java Source code

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Here is the source code for org.springframework.boot.actuate.metrics.export.MetricCopyExporter.java

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/*
 * Copyright 2012-2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.actuate.metrics.export;

import java.io.Flushable;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Iterator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.boot.actuate.metrics.Metric;
import org.springframework.boot.actuate.metrics.reader.MetricReader;
import org.springframework.boot.actuate.metrics.writer.CompositeMetricWriter;
import org.springframework.boot.actuate.metrics.writer.MetricWriter;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.PatternMatchUtils;
import org.springframework.util.ReflectionUtils;

/**
 * {@link Exporter} that "exports" by copying metric data from a source
 * {@link MetricReader} to a destination {@link MetricWriter}.
 *
 * @author Dave Syer
 * @since 1.3.0
 */
public class MetricCopyExporter extends AbstractMetricExporter {

    private static final Log logger = LogFactory.getLog(MetricCopyExporter.class);

    private final MetricReader reader;

    private final MetricWriter writer;

    private String[] includes = new String[0];

    private String[] excludes = new String[0];

    /**
     * Create a new {@link MetricCopyExporter} instance.
     * @param reader the metric reader
     * @param writer the metric writer
     */
    public MetricCopyExporter(MetricReader reader, MetricWriter writer) {
        this(reader, writer, "");
    }

    /**
     * Create a new {@link MetricCopyExporter} instance.
     * @param reader the metric reader
     * @param writer the metric writer
     * @param prefix the name prefix
     */
    public MetricCopyExporter(MetricReader reader, MetricWriter writer, String prefix) {
        super(prefix);
        this.reader = reader;
        this.writer = writer;
    }

    /**
     * Set the include patterns used to filter metrics.
     * @param includes the include patterns
     */
    public void setIncludes(String... includes) {
        if (includes != null) {
            this.includes = includes;
        }
    }

    /**
     * Set the exclude patterns used to filter metrics.
     * @param excludes the exclude patterns
     */
    public void setExcludes(String... excludes) {
        if (excludes != null) {
            this.excludes = excludes;
        }
    }

    @Override
    protected Iterable<Metric<?>> next(String group) {
        if (ObjectUtils.isEmpty(this.includes) && ObjectUtils.isEmpty(this.excludes)) {
            return this.reader.findAll();
        }
        return new PatternMatchingIterable(MetricCopyExporter.this.reader);
    }

    @Override
    protected void write(String group, Collection<Metric<?>> values) {
        for (Metric<?> value : values) {
            this.writer.set(value);
        }
    }

    @Override
    public void flush() {
        flush(this.writer);
    }

    private void flush(MetricWriter writer) {
        if (writer instanceof CompositeMetricWriter) {
            for (MetricWriter child : (CompositeMetricWriter) writer) {
                flush(child);
            }
        }
        try {
            if (ClassUtils.isPresent("java.io.Flushable", null)) {
                if (writer instanceof Flushable) {
                    ((Flushable) writer).flush();
                    return;
                }
            }
            Method method = ReflectionUtils.findMethod(writer.getClass(), "flush");
            if (method != null) {
                ReflectionUtils.invokeMethod(method, writer);
            }
        } catch (Exception ex) {
            logger.warn("Could not flush MetricWriter: " + ex.getClass() + ": " + ex.getMessage());
        }
    }

    private class PatternMatchingIterable implements Iterable<Metric<?>> {

        private final MetricReader reader;

        PatternMatchingIterable(MetricReader reader) {
            this.reader = reader;
        }

        @Override
        public Iterator<Metric<?>> iterator() {
            return new PatternMatchingIterator(this.reader.findAll().iterator());
        }

    }

    private class PatternMatchingIterator implements Iterator<Metric<?>> {

        private Metric<?> buffer = null;

        private Iterator<Metric<?>> iterator;

        PatternMatchingIterator(Iterator<Metric<?>> iterator) {
            this.iterator = iterator;
        }

        @Override
        public boolean hasNext() {
            if (this.buffer != null) {
                return true;
            }
            this.buffer = findNext();
            return this.buffer != null;
        }

        private Metric<?> findNext() {
            while (this.iterator.hasNext()) {
                Metric<?> metric = this.iterator.next();
                if (isMatch(metric)) {
                    return metric;
                }
            }
            return null;
        }

        private boolean isMatch(Metric<?> metric) {
            String[] includes = MetricCopyExporter.this.includes;
            String[] excludes = MetricCopyExporter.this.excludes;
            String name = metric.getName();
            if (ObjectUtils.isEmpty(includes) || PatternMatchUtils.simpleMatch(includes, name)) {
                return !PatternMatchUtils.simpleMatch(excludes, name);
            }
            return false;
        }

        @Override
        public Metric<?> next() {
            Metric<?> metric = this.buffer;
            this.buffer = null;
            return metric;
        }

    };
}